1. Field of the Invention
The present invention relates to technology for efficiently compressing or encoding image data or storing or transmitting these data, using holographic fringe patterns.
This application is based on patent application No. Hei 9-137372 and No Hei 10-6216 filed in Japan, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Holography refers to a technique for reproducing wave fronts from physical objects by means of light diffraction. Commonly, this has developed as a method of positioning for stereoscopic photography. On the other hand, the hologram is a technique for recording optical holographic fringe patterns; these can be determined by means of calculations if the shape of a physical object to be displayed, the wavelength of reference light, and the like, are known. This has been the subject of research for a long period of time in the field of computer holograms. An important merit of such technology is that it is possible to produce a holographic fringe pattern by means of calculations even for objects which do not actually exist; the chief development of such technology has been in fields other than stereoscopic display such as optical communication devices, optical pickups for CD ROM devices, and the like.
An important feature of such holograms other than those used for stereoscopic display is the data redundancy thereof. In other words, there is little effect on the reproduced image even if a portion of the hologram is deleted. As a result, by recording three-dimensional data and image data as holographic fringe patterns, it is possible to achieve techniques which simultaneously support conventional image compression and encoding functions. However, in order to display the holographic fringe patterns as holograms, it is necessary to display the holographic fringe patterns, which contain an enormous number of pixels, in high resolution apparatuses. For this reason, commonly, it is not merely the case that the construction of display apparatuses for computer holograms is difficult, but also the amount of data required to produce the holographic fringe patterns themselves is enormous. For this reason, almost no research has been conducted into image compression/encoding technology employing such holograms.
Even if high resolution apparatuses have been realized as a result of recent developments in electrical display technology, the problem still remains that the amount of data corresponding to an image (a holographic fringe pattern) is enormous. For example, in the case of a 5 inch screen, approximately 8 G pixels or more are required to display a hologram. In contrast, HDTV requires about 2 M pixels, so that approximately 4,000 times the amount of data is required for one image. Conventionally, even if large capacity transmission technologies employing optical fibers or the like were established, the data compression technologies involved constitute difficult problems.